Onboard vapor recovery detection

ABSTRACT

An apparatus for detecting a vehicle having a vapor recovery system having a fuel dispenser configured to deliver fuel to a fuel tank of a vehicle, a vapor recovery system operatively associated with the fuel dispenser having a vapor path for removing fuel vapor expelled from the fuel tank of the vehicle during a fueling operation, and a hydrocarbon vapor sensor associated with the vapor path for sensing the fuel vapors in the vapor path, wherein when the vapor sensor does not sense fuel vapor during the fueling operation, the fuel dispenser determines the vehicle contains an onboard vapor recovery system. Once a vehicle having an onboard vapor recovery system is detected, the vapor recovery system is either shut off or adjusted during the fueling operation to minimize fugitive emissions.

BACKGROUND OF THE INVENTION

The present invention relates generally to vapor recovery systemsassociated with both automobiles and fuel dispensers and, moreparticularly, to a fuel dispenser vapor recovery system capable ofdetecting the presence of an onboard vapor recovery system in anautomobile. For the past several years, the Environmental ProtectionAgency has been proposing various regulations to limit the amount offuel vapor released into the atmosphere during the refueling of a motorvehicle. During a conventional or standard fueling operation, incomingfuel displaces fuel vapor from the head space of a fuel tank and outthrough the filler pipe into the atmosphere if not contained andrecovered. The air pollution resulting from this situation isundesirable. Currently, many fuel dispensing pumps at service stationsare equipped with vapor recovery systems that collect fuel vapor ventedfrom the fuel tank filler pipe during the fueling operation and transferthe vapor to a fuel storage tank.

Recently, onboard, or vehicle carried, fuel vapor recovery and storagesystems (commonly referred to as onboard recovery vapor recovery orORVR) have been developed in which the head space in the vehicle fueltank is vented through a charcoal-filled canister so that the vapor isabsorbed by the charcoal. Subsequently, the fuel vapor is withdrawn fromthe canister into the engine intake manifold for mixture and combustionwith the normal fuel and air mixture. Because the fuel tank head spacemust be vented to enable fuel to be withdrawn from the tank duringvehicle operation, this invention addresses a problem of the dischargeof fuel vapor through the atmospheric vent of the tank when ambientpressure and temperature conditions are such that vapor pressure withinthe fuel tank exceeds atmospheric pressure.

In typical ORVR systems, a canister outlet is connected to the intakemanifold of the vehicle engine through a normally closed purge valve.The canister is intermittently subjected to the intake manifold vacuumwith the opening and closing of the purge valve between the canister andintake manifold. A computer which monitors various vehicle operatingconditions controls the opening and closing of the purge valve to assurethat the fuel mixture established by the fuel injection system is notoverly enriched by the addition of fuel vapor from the canister to themixture.

Fuel dispensing systems having vacuum assisted vapor recovery capabilitywhich are unable to detect ORVR systems will waste energy, increase wearand tear, ingest excessive air into the underground storage tank andcause excessive pressure buildup in the underground storage tank due tothe expanded volume of hydrocarbon saturated air. Recognizing an ORVRsystem and adjusting the fuel dispenser's vapor recovery systemaccordingly eliminates the redundancy associated with operating twovapor recovery systems for one fueling operation. The problem ofincompatibility of assisted vapor recovery and ORVR was discussed in"Estimated Hydrocarbon Emissions of Phase II and Onboard Vapor RecoverySystems" dated Apr. 12, 1994, amended May 24, 1994, by the CaliforniaAir Resources Board. That paper suggests the use of a "smart" interfaceon a nozzle to detect an ORVR vehicle and close one vapor intake valveon the nozzle when an ORVR vehicle is being filled.

Adjusting the fuel dispenser's vapor recovery system will mitigatefugitive emissions by reducing underground tank pressure. Reducingunderground tank pressure minimizes the "breathing" associated withpressure differentials between the underground tank and ambient pressurelevels. If the vacuum created by the fuel dispenser's vapor recoverysystem is not reduced or shut off, the underground tank pressure willincrease to the extent that hydrocarbons are released through a pressurevacuum valve or breathing cap associated with the underground tank. Incertain applications, reducing the vacuum created by the fueldispenser's vapor recovery system when an ORVR system is detectedpermits the ingestion of a volume of air into the underground tank. Whensaturated with hydrocarbons, the volume of air expands to a volumeapproximately equal to the volume of fuel dispensed. Adjusting the fueldispenser's vapor recovery system in this manner minimizes breathinglosses associated with the underground tank.

Thus, there remains a need for a fuel dispensing system with a vaporrecovery system having the ability to detect a vehicle having an ORVRsystem and adjusting its vapor recovery system when an ORVR system isdetected to reduce breathing losses and wear and tear, as well asconserve energy.

SUMMARY OF THE INVENTION

A. Hydrocarbon Sensing

The present invention is directed to a gasoline dispenser having a vaporrecovery system capable of detecting a vehicle having an onboard vaporrecovery system. One aspect of the present invention is to adjust thedispenser's vapor recovery system in a manner to complement thevehicle's onboard vapor recovery system during the fueling operationupon the dispenser's vapor recovery system sensing that the vehicle hasan onboard vapor recovery system, whereby the respective vapor recoverysystems operate in conjunction to maximize fuel vapor recovery.

Still another aspect of the invention is to provide a system fordetecting a vehicle having a refueling vapor recovery system whichincludes a fuel dispenser configured to deliver fuel to a fuel tank of avehicle, a vapor recovery system operatively associated with the fueldispenser having a vapor path for removing fuel vapor expelled from thefuel tank of the vehicle during a fueling operation, and a vapor sensorassociated with said vapor path for sensing the fuel vapors in the vaporpath, wherein when the vapor sensor does not sense fuel vapor during thefueling operation, the fuel dispenser determines the vehicle contains avapor recovery system. The vapor sensor may be any type of a widevariety of available hydrocarbon sensors.

The vapor sensor may also be made up of an infrared emitter anddetector. The infrared emitter transmits infrared waves to the infrareddetector through a portion of the vapor path. The vapor sensor can sensethe amount of attenuation in a portion of the infrared spectrum causedby any absorption of infrared by hydrocarbons present in the vapor path.The infrared emitter may be a solid state or a black body radiator. Thedetector may be solid state pyro-electric. These sensor configurationsmay include the use of piezoelectric crystal embodiments. Additionally,an optical bandpass filter may be used to narrow sensor sensitivity tocertain desired wavelengths. In a preferred embodiment, the vapor sensoris a fiber-optic sensor configured to sense hydrocarbons. Fiber opticsprovide an intrinsically safe passage for any signals emanating from thevapor sensor. Other configurations will become apparent to those skilledin the art. These configurations are considered within the scope ofapplicants' invention.

In the above-mentioned aspects, once a vehicle having a vapor recoverysystem is detected, the vapor recovery system of the dispenser may bedeactivated, adjusted or have its vapor flow path redirected toatmosphere. Venting the vapor path to atmosphere once an ORVR equippedvehicle is detected appears preferable in applications using liquiddriven vapor pumps. The dispenser's vapor recovery system may beadjusted to reduce the vacuum in the vapor recovery path and thereforereduce the rate of vapor flow in the path. In certain applications,minimum vapor flow through the vapor path allows the dispenser tocontinuously monitor the conditions in the vapor path for errorchecking, such as assuring a mistake was not made in initialidentification of an ORVR equipped vehicle, or to determine if thevehicle's vapor recovery system quits working.

Another aspect of the present invention is to provide a method fordetecting a vehicle having a vapor recovery system including deliveringfuel to a fuel tank of a vehicle from a fuel dispenser, recovering vaporexpelled from the fuel tank of the vehicle during a fueling operationwith a vapor recovery system through a vapor recovery path operativelyassociated with the fuel dispenser for removing fuel vapor, sensing ahydrocarbon level in the vapor recovery path and determining whether thevehicle has an onboard vapor recovery system from the hydrocarbon levelsensed in the sensing step. The method includes controlling the vaporrecovery system in the dispenser according to the hydrocarbon levelssensed in the sensing step, deactivating the vapor recovery system orredirecting airflow in the vapor recovery path to atmosphere.

B. Pressure Sensing

Another aspect of the present invention is to provide a fuel dispenserconfigured to deliver fuel to the fuel tank of a vehicle, a vaporrecovery system having a vapor recovery path operatively associated withthe fuel dispenser for removing fuel vapor expelled from the fuel tankof the vehicle during a fueling operation, and a pressure sensoroperatively associated with the fuel dispenser for sensing an increasein vacuum in the vapor recovery path due to a vapor recovery systemassociated with the vehicle working in opposition to the vapor recoverysystem of the fuel dispenser. The pressure sensor may be located near anozzle for dispensing fuel into the vehicle's fuel tank, anywhere alonga vapor return line, including inside a vapor recovery pump.

The pressure sensor located near the nozzle may be inside a bootconcentrically mounted about the nozzle and configured to sealablyengage a vehicle's filler pipe to form a vacuum chamber operativelyconnected to the vapor recovery system for removing vapors during afueling operation.

Yet another aspect of the present invention is to provide a method fordetecting a vehicle having a vapor recovery system including deliveringfuel to a fuel tank of a vehicle from a fuel dispenser, recovering vaporexpelled from the fuel tank of the vehicle during a fueling operationwith a vapor recovery system through a vapor recovery path operativelyassociated with the fuel dispenser, and sensing an increase in vacuum inthe vapor recovery path due to a vapor recovery system associated withthe vehicle working in opposition to the vapor recovery system of thefuel dispenser. Upon detection of a vehicle having a vapor recoverysystem, in the method the fuel dispenser either controls its vaporrecovery system according to the vacuum sensing step or completelydeactivates the vapor recovery system. A third option is to redirect theair flow in the vapor recovery path to atmosphere upon detection of avehicle having a vapor recovery system.

These and other aspects of the present invention will become apparent tothose skilled in the art after a reading of the following description ofthe preferred embodiments when considered in conjunction with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational and partial sectional view of a typicalgasoline dispenser having a vapor recovery system.

FIG. 2 depicts a typical vacuum assist vapor recovery nozzle and thecross section of a fuel tank of a vehicle equipped with onboard recoveryvapor recovery.

FIG. 3 is an elevational and partial sectional view of a typicalgasoline dispenser having a vapor recovery system using a liquid drivenvapor pump and an atmospheric vent associated with a vapor passageway.

FIG. 4 is a perspective view of a fuel dispenser hose configured for usewith a gasoline dispenser having a vapor recovery system.

FIG. 5 is a cross-sectional view of a gasoline dispenser hose having asensor in the vapor return path.

FIG. 6 is an enlarged perspective view of a fiber-optic hydrocarbonsensor.

FIG. 7 is a cross-sectional view of a vapor return passage having aninfrared transmitter and receiver.

FIG. 8 is a schematic block diagram of a portion of the gasolinedispenser's vapor recovery control system.

FIG. 9 is a perspective view of a module for diverting vapor flow forhydrocarbon sensing.

FIG. 10 is an elevational and partial sectional view of a booted fueldispensing hose and nozzle inserted into a motor vehicle gasoline tankhaving an onboard vapor recovery system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A. Hydrocarbon Sensing

Referring now to the drawings in general and FIG. 1 in particular, itwill be understood that the illustrations are for the purpose ofdescribing a preferred embodiment of the invention and are not intendedto limit the invention thereto. As best seen in FIG. 1, in a typicalservice station, an automobile 100 is shown being fueled from a gasolinedispenser or pump 18. A spout 28 of nozzle 2 is shown inserted into afiller pipe 22 of a fuel tank 20 during the refueling of the automobile100.

A fuel delivery hose 4 having vapor recovery capability is connected atone end to the nozzle 2, and at its other end to the fuel dispenser 18.As shown by the cutaway view of the interior of the fuel delivery hose4, an annular fuel delivery passageway 12 is formed within the fueldelivery hose 4 for distributing gasoline pumped from an undergroundstorage tank 5 to the nozzle 2. Also within the fuel delivery hose 4 isa tubular vapor recovery passageway 8 for transferring fuel vaporsexpelled from the vehicle's fuel tank 20 to the underground storage tank5 during the fueling of a vehicle that is not equipped with an onboardvapor recovery system. The fuel delivery hose 4 is depicted as having aninternal vapor recovery hose 10 for creating the vapor recovery passage8. The fuel delivery passageway 12 is formed between the hose 10 andhose 4.

A vapor recovery pump 14 provides a vacuum in the vapor recovery passage8 for removing fuel vapor during a refueling operation. The vaporrecovery pump 14 may be placed anywhere along the vapor recovery passage8 between the nozzle 2 and the underground fuel storage tank. The vaporrecovery system using the pump 14 may be any suitable system such asthose shown in U.S. Pat. No. 5,040,577 to Pope, 5,195,564 to Spalding,5,333,655 to Bergamini et al., or 3,016,928 to Brandt. Various ones ofthese systems are now in commercial use, recovering vapor duringrefueling of conventional, non-ORVR vehicles. The present inventionaddresses an adaptation of those systems for use with ORVR vehicles.

Turning now to FIG. 2, the vehicle fuel tank 20 of an ORVR vehicle hasan associated onboard vapor recovery system 24. These onboard vaporrecovery systems 24 typically have a vapor recovery inlet 26 extendinginto the tank 20 (as shown) or the filler pipe 22 and communicating withthe vapor recovery system 24. In the ORVR system of FIG. 2, incomingfuel provides a seal in fill neck 22 to prevent vapors from within thetank 20 to escape. This sealing action is often referred to as a liquidseal. As the tank fills, pressure within tank 20 increases and forcesvapors into the vapor recovery system 24 through the vapor recoveryinlet 26. Other ORVR systems may use a check valve 21 along the fillneck 22 to prevent further loss of vapors. The check valve 21 isnormally closed and opens when a set amount of gasoline accumulates overthe check valve within the fill neck 22.

The spout 28 has numerous apertures 29. The apertures 29 provide aninlet for fuel vapors to enter the vapor recovery path 8 of fueldispenser 18 from the vehicle's filler pipe 22. As liquid fuel rushesinto the fuel tank 20 during a fueling of a vehicle not equipped with anORVR system, fuel vapors are forced out of the fuel tank 20 through thefill pipe 22. The fuel dispenser's vapor recovery system pulls fuelvapor through the vapor recovery apertures 29, along the vapor recoverypath 8 and ultimately into the underground tank 5 (as shown in FIG. 1).

As shown in FIG. 1, the underground tank 5 includes a vent 17 and apressure-vacuum vent valve 19 for venting the underground tank 5 toatmosphere. The vent 17 and vent valve 19 allow the underground tank 5to breathe in order to substantially equalize the ambient and tankpressures. In typical applications, maintaining tank pressure betweenthe limits of pressure and vacuum is sufficient. Typical ranges ofpressure and vacuum will range between +3 inches of water to -8 inchesof water.

FIGS. 4 and 5 depict partial and complete cross-sectional views of thefuel dispenser hose 4. In an embodiment of the current invention, ahydrocarbon sensor 32 is placed inside the vapor passage 8 to detect thepresence or absence of hydrocarbons associated with fuel vapors. Anabsence of hydrocarbons in the vapor passage 8 indicates the presence ofan onboard vapor recovery system in the vehicle being fueled. If anonboard system is detected, the dispenser could either shut off thevapor pump 14 completely, or calculate and control the pump 14 to supplythe amount of air to the storage tank needed to replenish the volume ofliquid taken from the tank 5 and thus eliminate breathing losses. Thehydrocarbon sensor 32 may be located anywhere along the vapor recoverypassage 8, including within the vapor recovery pump 14. Certainapplications will locate the hydrocarbon sensor 32 at either, or both,an inlet or outlet to the vapor recovery pump 14.

In one embodiment, the hydrocarbon sensor 32 is a fiber-optic sensor 44capable of sensing an amount of hydrocarbons present in the vapor returnpassage 8. The fiber-optic sensor 44 is shown in detail in FIG. 6.Preferably, the fiber-optic sensor 44 uses two fiber-optic light rails46, a sense fiber 46a and a reference fiber 46b. The sense fiber 46a hasa special coating and the reference fiber 46b is isolated. The lightrails 46a and 46b run between a single light source 48 and twophotodetectors 50. The photodetectors 50 may be photodiodes. Therefractive index of the sense fiber 46a changes when in contact withhydrocarbon vapor, causing the fiber to lose light through its surface.This loss of light is proportional to the concentration of hydrocarbonvapor. The amount of light transmitted by the reference fiber 46b iscompared to the amount transmitted by the sense fiber 46a. Since theyshare the same light source 48, any change in the output voltages at thephotodetectors 50 can be attributed to the losses from the side of fiber46a caused by the concentration of the vapor stream.

As seen in FIG. 7, another embodiment of the current invention employsan infrared emitter 34 and an infrared detector 36 as a hydrocarbonsensor in the tubing 10. Preferably, the infrared emitter 34 is either asolid state or a black body radiator with an appropriate filter, ifrequired, irradiating through a cross-section of sampled vapor 40 to theinfrared detector 36. An optical bandpass filter 39 may be used tonarrow the sensor sensitivity to certain wavelengths. The infrareddetector 36 is either solid state or pyro-electric infrared (PIR).

The attenuation in the infrared spectrum 38 caused by the absorption ofinfrared by hydrocarbons is detected by detector 36. When the amount ofhydrocarbons to absorb the infrared falls from an expected level duringoperation, the fuel dispenser may disable or adjust its vapor recoverysystem.

In the preferred embodiments of the current invention, there is aresponse time of less than 6 seconds from the beginning of the fuelingoperation or within delivering one gallon of fuel before detectingwhether fuel vapors are normal, present in abnormally low quantities, ornot present. The absence or low concentration of hydrocarbons indicatesthat the vehicle is equipped with an onboard vapor recovery system.

The dispenser electronics, as depicted in block diagram in FIG. 8,process a resulting signal 54 from the sensor, whether it be offiber-optic sensor 44, IR detector 36 or some other sensor, and takeappropriate action. The action could take any of several forms. Thevapor return pump 14 could slow down in order to reduce the effectivevacuum, thereby reducing the effect of vapor growth which the ingestionof clean air often creates. Breathing losses are a major cause offugitive emissions. If the underground tank pressure is greater than theambient pressure, hydrocarbon saturated fuel vapor is released into theatmosphere through pressure-vacuum valve 19. In contrast, if thepressure in tank 5 is less than that of the ambient, vent 19 allowsfresh air into tank 5 to equalize the pressure. The fresh air becomessaturated with hydrocarbons and increases the pressure within the tank 5and hydrocarbon laden vapor is then released to ambient through vent 19.As the tank continues to "breathe" in this manner, hydrocarbons arerepeatedly released to atmosphere. Thus, it is important to minimize anypressure differential between tank 5 and the atmosphere to prevent theingestion of air.

When fueling a standard or non-ORVR equipped vehicle, the vapor recoverysystem of fuel dispenser 18 pulls in enough hydrocarbon vapor and airmixture to compensate for the dispensed liquid fuel and minimizebreathing losses. When an ORVR equipped vehicle is detected, thedispenser compensates for the vapor recovered by the vehicle's ORVRsystem by pulling in ambient air.

Upon detection of an ORVR equipped vehicle, slowing down the vaporreturn pump 14 allows for continuous monitoring of the vaporconcentration in the vapor return passage 8 to ensure that a mistake wasnot made in the initial identification of an onboard vapor recoverysystem associated with the vehicle. Alternatively, the vapor recoverypump 14 could simply shut down until the next transaction. Otherembodiments of the current invention may forego shutting down the fueldispenser's vapor recovery system. For example, the system may redirectthe flow of air from the apertures 29 through vapor passage 8 to ambientthrough valve 15 (see FIG. 3). This may be used when the vapor recoverysystem of the dispenser 18 uses a liquid driven vapor pump 14.Redirecting flow to ambient will prevent over pressurizing theunderground tank and reduce breathing losses.

The various sensors, such as the hydrocarbon sensor 32 or the infrareddetection sensor 36 provide a signal 54 to a central processing unit(CPU) 56. The CPU 56 evaluates the signal 54 to determine whether thevehicle being fueled has an onboard vapor recovery system. Accordingly,the CPU 56 provides a control signal 58 to a vapor recovery pumpcontroller 60. The vapor recovery pump controller 60 then controls thevapor recovery pump 14 with control signal 62.

As shown in FIG. 9, any of the hydrocarbon sensors 32 may be installedwithin a separate module 64 designed to divert the flow path of acertain amount of fuel vapors. The module 64 may split the vapor path 8into two vapor paths 8a, 8b. The hydrocarbon sensor is installed in onevapor path 8b. In the fiber-optic sensor embodiment, vapor path 8b ofmodule 64 may be designed so that only a fraction of the hydrocarbonvapor and air mixture flows over the probe 44.

Once detection of a vehicle equipped with an onboard vapor recoverysystem occurs, various vapor recovery control options are available.Disabling the fuel dispenser's vapor recovery system reduces undergroundfuel tank pressure and thereby reduces losses due to fugitive emissionsand reduces wear and unnecessary use of assist type vapor recoverysystems when operation would be redundant. Alternatively, thedispenser's vapor recovery system is adjusted to reduce the vacuumcreated by the fuel dispenser during the fueling of an onboard vaporrecovery equipped vehicle. The vapor recovery system provides enoughambient air to the underground tank 5, that when the air saturates, thehydrocarbon saturated air volume is approximately equal to the amount offuel dispensed; thereby minimizing pressure fluctuation in theunderground tanks. Another option, particularly useful with liquiddriven vapor pumps, is to use an output of CPU 56 to open valve 15 toredirect the airflow in the vapor recovery passage 8 to atmospherethrough the vapor passage vent valve 15 (as shown in FIG. 3).

Adjusting the vacuum created by the fuel dispenser's vapor recoverysystem prevents over pressurizing the underground fuel tanks, thusmitigating fugitive emissions. Fugitive emissions is a collective termfor emissions from the vent 19 or any other leak path to the atmosphereat the dispensing facility.

The current invention may adjust the fuel dispenser's vapor recoverysystem to compensate for both vapor shrink and vapor growth conditions.Typically, during vapor shrink conditions, an amount of air greater thanthe volume of liquid dispensed is drawn into the tank 5. Vapor shrinkconditions usually occur during hot summer months when the ambienttemperature is high and the tank temperature is relatively cool. As theair is drawn into the tank, the air contracts. The fuel dispensercompensates for this decrease in volume by increasing the amount of airpulled into the underground tank 5.

In contrast with the vapor shrink conditions, vapor growth conditionstypically occur during winter months when the ambient temperature is lowand the tank temperature is relatively high. Under vapor growthconditions, the air pulled into the tank expands when subjected to thewarmer tank temperatures. The fuel dispenser's vapor recovery systempulls in an amount of air less than the amount of fuel dispensed tocompensate for the volume expansion in the tank. The CPU 56 of fueldispenser 18 may receive temperature data from an ambient temperaturesensor 66 and an underground tank temperature sensor 68 (see FIG. 1).Alternatively, rough air ingestion compensation may be accomplished byhaving predefined flow settings for various times of the day or year.For example, the recovery system can be set to ingest air or vapormixture in an amount equal to two-thirds the volume of fuel dispensed,thus allowing the air or vapor mixture to expand by a factor ofapproximately 1.4 or 1.5 to fill the tank volume when saturated.

Also, the fuel dispenser's vapor recovery system continually monitorsthe vapor concentration to ensure an initial mistake was not made indetermining whether or not the vehicle being fueled has an ORVR systemor if a malfunction in the vehicle's ORVR system occurs. In either ofthe latter two cases, the fuel dispenser's vapor recovery system resumesvapor recovery accordingly.

The disclosed and claimed invention also encompasses kits, modules andthe like for retrofitting pre-existing dispensers to enable ORVRequipped vehicle detection. For retrofitting, sensor modules areconfigured to operatively associate with existing pump electronics (seeFIG. 8). For example, the sensor and/or sensor module is placed along orwithin the vapor passage 8 to sense hydrocarbon levels. Preferably, thesensor or module is placed within the vapor passage 8 at points allowingthe easiest and most economical access to the vapor path, such as at theinlet or outlet of the vapor pump 14, or other connection points in thesystem.

B. Pressure Sensing

In an alternative embodiment for booted vapor recovery systems, as shownin FIG. 10, the nozzle 2 includes a vapor recovery boot 6 for preventingfuel vapors from escaping to atmosphere during the vapor recoveryprocess. The vapor recovery boot 6 of nozzle 2 forms an annular chamberabout nozzle 28 and sealably engages the end of filler pipe 22 toprevent the escape of fuel vapors to atmosphere. The annular chamberformed by vapor recovery boot 6 and the nozzle spout 28 operativelycommunicates with the vapor recovery passage 8. A pressure sensor 30 isplaced in the annular chamber formed by the vapor recovery boot 6 andthe nozzle spout 28 to detect an increase in vacuum associated with thevehicle's onboard vapor recovery system working in opposition to thefuel dispenser's vapor recovery system. In this embodiment, theincreased vacuum may trip the nozzle's automatic shutoff venturimechanism (not shown) and therefore make fueling extremely difficult ifnot impossible. Therefore, it is preferable that the seal between thevapor recovery boot 6 and the filler pipe 22 is only semi-tight and thevapor recovery system is vented via valve 15 to allow normal fueling.

Additionally, equipping the vapor recovery boot 6 with an orifice 16designed to allow a vacuum in excess of 20-25 inches to be developed inthe fill pipe area when fueling a vehicle equipped with an onboard vaporrecovery system will eliminate premature cut-off. This level of vacuumis high enough to be recognized by the fueling system, but not enough totrip the automatic shutoff mechanism of the nozzle 2. The increase inthe vacuum may be detected by placing the sensor 30 in the boot area asshown, at the vapor recovery pump 14, or anywhere along the vaporrecovery passage 8.

Certain modifications and improvements will occur to those skilled inthe art upon a reading of the foregoing description. It should beunderstood that all such modifications and improvements have beendeleted herein for the sake of conciseness and readability but areproperly within the scope of the following claims.

We claim:
 1. An apparatus for dispensing fuel and detecting a vehiclehaving a vapor recovery system comprising:a fuel dispenser configured todeliver fuel to a fuel tank of vehicle; a vapor recovery systemoperatively associated with said fuel dispenser having a vapor path forremoving fuel vapor expelled from the fuel tank of the vehicle during afueling operation; a hydrocarbon vapor sensor associated with said vaporpath for sensing the fuel vapors in said vapor path and providing avapor signal indicative of a presence of hydrocarbon vapor; and a vaporrecovery controller configured to:a) receive the vapor signal; b)determine whether or not the vehicle has a vapor recovery system basedon hydrocarbon vapor concentration in said vapor path during fueling;and c) shut off or adjust said vapor recovery system during the fuelingoperation upon determining that the vehicle has a vapor recovery system.2. An apparatus as claimed in claim 1 wherein said vapor sensorcomprises an infra-red emitter and detector.
 3. An apparatus as claimedin claim 1 wherein said vapor sensor includes a piezoelectric crystal.4. An apparatus as claimed in claim 2 wherein said infra-red emitter anddetector are pyro-electric.
 5. An apparatus as claimed in claim 2wherein said infra-red emitter transmits infra-red waves to saidinfra-red detector through a portion of said vapor path, said vaporsensor sensing an amount of attenuation in a portion of the infra-redspectrum caused by absorption of infra-red by hydrocarbons present insaid vapor path.
 6. An apparatus as claimed in claim 2 furthercomprising a filter operatively associated with said sensor, said filterconfigured to narrow sensor sensitivity to certain wavelengths.
 7. Anapparatus as claimed in claim 1 further comprising a vent for ventingsaid vapor path to atmosphere upon detection of a vehicle having a vaporrecovery system.
 8. An apparatus as claimed in claim 1 wherein saidvapor recovery system uses a liquid driven vapor recovery pumpoperatively associated with said vapor recovery path, said pump drivenby the fuel delivered to the vehicle.
 9. An apparatus as claimed inclaim 1, wherein said dispenser's vapor recovery system continues tomonitor said vapor path after detection of a vehicle having a vaporrecovery system.
 10. An apparatus as claimed in claim 9 wherein saidvapor recovery system resumes substantial vapor recovery if the vaporrecovery system of the vehicle malfunctions.
 11. An apparatus as claimedin claim 1 wherein said controller is configured to adjust vaporrecovery to pull in an amount of air or hydrocarbon vapor mixture toreduce breathing losses.
 12. An apparatus as claimed in claim 2 whereinsaid infra-red emitter is a black body radiator irradiating through aportion of said vapor path.
 13. An apparatus as claimed in claim 2wherein a sample of gas in said vapor path is subjected to said vaporsensor.
 14. An apparatus as claimed in claim 2 wherein said vapor sensoracts upon a gas in said vapor path continuously during a fueling.
 15. Anapparatus as claimed in claim 1 wherein said vapor recovery system isadjusted by said vapor recovery controller in a manner to assist vaporrecovery during the fueling operation upon the sensing of a vehiclehaving a vapor recovery system, whereby the respective vapor recoverysystems operate in conjunction to maximize fuel vapor recovery.
 16. Anapparatus as claimed in claim 1 wherein said sensor is configured tosense hydrocarbon concentrations during fueling operations of vehicleshaving vapor recovery systems.
 17. An apparatus as claimed in claim 1wherein said sensor is a fiber-optic sensor configured to sensehydrocarbons.
 18. A method for dispensing fuel and detecting a vehiclehaving a vapor recovery system comprising:delivering fuel to a fuel tankof a vehicle from a fuel dispenser having a vapor recovery system with avapor recovery path operatively associated with the fuel dispenser forremoving fuel vapor expelled from the fuel tank of the vehicle during afueling operation; sensing a presence of hydrocarbon in the vaporrecovery path; and determining whether the vehicle has an onboard vaporrecovery system from the hydrocarbon level sensed in the sensing step.19. A method as claimed in claim 18 further comprising controlling thevapor recovery system of the fuel dispenser according to a concentrationof hydrocarbons sensed in the sensing step.
 20. A method as claimed inclaim 19 wherein said controlling step includes adjusting vapor recoveryto pull in an amount of air or hydrocarbon vapor mixture to reducebreathing losses.
 21. A method as claimed in claim 18 further comprisingredirecting air flow in the vapor recovery path to atmosphere upondetection of a vehicle having a vapor recovery system.
 22. A method asclaimed in claim 18 further comprising deactivating the vapor recoverysystem of the fuel dispenser upon detection of a vehicle having a vaporrecovery system.
 23. An apparatus for adding to a fuel dispenser fordetecting a vehicle having a vapor recovery system whereinthe fueldispenser is configured to deliver fuel to a fuel tank of a vehicle,said fuel dispenser including a vapor recovery system operativelyassociated with said fuel dispenser having a vapor path for removingfuel vapor expelled from the fuel tank of the vehicle during a fuelingoperation and a vapor recovery controller, said apparatus comprising:ahydrocarbon sensor module configured to operatively associate with saidvapor path for sensing the fuel vapors in said vapor path, a signal pathoperatively associated with said module and the controller to provide avapor signal indicative of a presence of hydrocarbons in said vapor pathto the vapor recovery controller; and a software update for thecontroller to adapt the controller to determine whether or not thevehicle has a vapor recovery system and to shut off or adjust said vaporrecovery system during the fueling operation upon the sensing of avehicle having a vapor recovery system.